GB1071455A - Gyromagnetic resonance apparatus - Google Patents

Abstract

1,071,455. Gyromagnetic resonance apparatus. VARIAN ASSOCIATES. March 23, 1965 [April 24, 1964], No. 12321/65. Heading G1N. In a spin decoupling arrangement, for a gyromagnetic apparatus wherein a sample-containing probe 10, Fig. 1 is situated in a polarizing magnetic field H o provided by magnetic poles 12, and wherein one radio frequency signal from a generator 14 is applied to the probe for orienting a group of atom portions to be observed in the sample, a second r.f. signal is also applied to the probe from a generator 32 to decouple secondary atom portions from the portions to be observed, and both the undesirable tilting of the spin axis of the observed atom portions caused by the second signal and the tendency of the spins of the observed and secondary atom portions to recouple, are obviated by applying to the probe a third r.f. signal from a generator 34. The combined effect of the second and third signals decouples effectively the secondary portions but leaves the observed portions unaffected. A low frequency (e.g. 2 Kc/s) oscillator 16 modulates the polarizing field H o so that the frequency of the orienting signal from generator 14 (e.g. 60 Mc/s) is effectively regularly swept through the resonant frequency of the atom portions to be observed. A detector in the probe generates an output signal which is amplified at 20, and phase-detected, first at 24 with reference to the orienting signal from generator 14, and then at 28 with reference to the low frequency of oscillator 16, the output of the phase-detector 28 producing on a recorder 30 the spectral trace of the atom portions under test. The frequencies of the second and third r.f. signal generators 32, 34 may be, for example, 60 Mc Π100 c/s respectively. In a second embodiment Fig. 3 (not shown) a substantially similar system is used, but in this case, the second and third r.f. generators (40, 44) modulate the polarizing field (produced by oscillator 36) and produce with the orienting r.f. signal (from 14) two sideband frequencies which effect the required decoupling and tilt compensation.